Cookies are stored on your computer by websites you visit and contain information such as site preferences or login status. This article describes how to block websites from storing cookies in Firefox.

Viewing a list of blocked sites

To see a list of sites that you have blocked from setting cookies:

At the top of the Firefox window, click on the Firefox button and then select Options.At the top of the Firefox window, click on the Tools menu and then select Options.On the menu bar, click on the Firefox menu and select Preferences....At the top of the Firefox window, click on the Edit menu and select Preferences.

Click the menu button
and choose Options.Preferences.

Select the Privacy panel.

Set Firefox will: to Use custom settings for history.

Next to Accept cookies from sites, click Exceptions….

Block cookies for all sites

To set Firefox to block cookies from all websites:

At the top of the Firefox window, click on the Firefox button and then select Options.At the top of the Firefox window, click on the Tools menu and then select Options.On the menu bar, click on the Firefox menu and select Preferences....At the top of the Firefox window, click on the Edit menu and select Preferences.

Click the menu button
and choose Options.Preferences.

Select the Privacy panel.

Set Firefox will: to Use custom settings for history.

Remove the check mark from Accept cookies from sites.

Click OK to close the Options window.Click Close to close the Preferences window.Close the Preferences window.Close the about:preferences page. Any changes you've made will automatically be saved.